發(fā)布時間：2018-01-12 23:16

  本文關(guān)鍵詞：一級公路路基拓寬差異沉降影響因素及控制標(biāo)準(zhǔn)分析　出處：《合肥工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 一級公路 路基拓寬 差異沉降 影響因素 控制指標(biāo)

【摘要】：在一級公路改造工程設(shè)計施工過程及道路運營階段中,新老路基間的差異沉降問題不可避免,為分析研究一級公路拓寬路基差異沉降關(guān)鍵影響因素及其控制標(biāo)準(zhǔn)問題,本文依托實際工程,選取ABAQUS分析軟件采用有限元法基于飽和土單向固結(jié)理論對一級公路拓寬路基差異沉降進(jìn)行計算,分析探討了路基拓寬寬度、路基高度、路基填料模量、路基模量關(guān)鍵因素對差異沉降的影響,并從設(shè)計、施工以及路面結(jié)構(gòu)使用角度研究拓寬路基差異沉降控制指標(biāo),得出以下研究結(jié)論：(1)分析一級公路路基拓寬工程的主要病害形式,總結(jié)路基差異沉降形成原因主要包括拓寬路基壓實度不足、高填方路基、新老路基結(jié)合部強(qiáng)度不足等,在設(shè)計和施工各環(huán)節(jié)應(yīng)針對形成原因采取有效工程措施來避免或減少不均勻沉降。(2)拓寬路基頂面沉降變化曲線總體呈“勺”形變化,老路路基和拓寬路基的總體等效應(yīng)力水平雖不大,但在新拓寬路基頂部中間位置出現(xiàn)應(yīng)力集中現(xiàn)象,在實際拓寬路基施工中需在路基結(jié)合部加鋪土工格柵等措施來防止應(yīng)力過大導(dǎo)致結(jié)構(gòu)層發(fā)生破壞。(3)采用正交試驗設(shè)計法對路基拓寬寬度、路基高度、路基填料模量、路基模量四個拓寬路基差異沉降關(guān)鍵因素進(jìn)行綜合分析,以路基頂面豎向沉降和水平位移為考核指標(biāo),得出對豎向沉降影響程度最大的影響因素為路基拓寬寬度。(4)對路基不同拓寬方式在不同拓寬寬度情況下的路基頂面沉降進(jìn)行分析可知,當(dāng)路基拓寬寬度增加至8m后,拓寬路基最大沉降出現(xiàn)位置處出現(xiàn)了反坡效應(yīng),建議單側(cè)拓寬寬度以8-12m為宜。(5)對不同路基填土高度時拓寬路基頂面差異沉降變化分析可知,隨著路基填土高度不斷增大,拓寬路基中差異沉降值逐漸增大；路基土的彈性模量對于新拓寬的路基部分影響程度較大,隨著彈性模量增加,新拓寬路基頂面不均勻沉降量呈下降趨勢,施工時路基土的各項特性需通過現(xiàn)場試驗嚴(yán)格保證。(6)經(jīng)探討研究,建議在施工完成時以橫坡斜率偏差i≤0.3%作為檢驗道路工程施工質(zhì)量控制指標(biāo),以路面變坡率i ≤0.46%作為路面結(jié)構(gòu)使用階段差異沉降控制標(biāo)準(zhǔn)；本文建立的路基拓寬差異沉降限值S與新老路基拓寬比l、新路基填料彈性模量比k、路基高度h間的擬合方程式能較真實反映影響因素與路基拓寬差異沉降控制指標(biāo)的內(nèi)在規(guī)律,可為實際路基拓寬工程的設(shè)計與施工提供參考。
[Abstract]:In the design and construction process of the first class highway reconstruction project and the road operation stage, the differential settlement between the new and old subgrade is inevitable. In order to analyze and study the key factors and control standards of differential settlement of widening subgrade of first class highway, this paper relies on actual engineering. Based on the unidirectional consolidation theory of saturated soil, the differential settlement of the first grade highway widening roadbed is calculated by using the ABAQUS analysis software, and the width and height of the roadbed widening are analyzed and discussed. The influence of the key factors of subgrade filling modulus and subgrade modulus on differential settlement is discussed. The control index of widening subgrade differential settlement is studied from the angles of design, construction and pavement structure use. Draw the following conclusion: 1) analyze the main disease forms of the first class highway roadbed widening project, summarize the causes of the subgrade differential settlement, including the lack of compaction degree of the widening roadbed, high filling subgrade. The strength of the new and old roadbed joint is insufficient. In design and construction, effective engineering measures should be taken to avoid or reduce uneven settlement. Although the overall equivalent stress level of the old roadbed and the widening roadbed is not large, the stress concentration appears in the middle position of the new widening roadbed. In the actual widening of roadbed construction, some measures such as adding geogrid to the junction of roadbed are needed to prevent the damage of structural layer caused by excessive stress.) the orthogonal test design method is used to widen the width and height of roadbed. The four key factors of widening the differential settlement of subgrade are comprehensively analyzed, and the vertical settlement and horizontal displacement of the top surface of the roadbed are taken as the evaluation index. It is concluded that the most influential factor of vertical settlement is the width of roadbed widening. 4) the settlement of the top surface of subgrade with different widening ways is analyzed. When the width of roadbed widening is increased to 8 m, the reverse slope effect occurs at the position where the maximum settlement of the widening roadbed appears. It is suggested that the width of unilateral widening should be 8-12m.) the analysis of the differential settlement of the top surface of widening roadbed with different filling height of roadbed shows that the height of embankment is increasing with the increase of the height of embankment. The differential settlement value in widening roadbed increases gradually; The elastic modulus of subgrade soil has a great influence on the newly widened subgrade. With the increase of elastic modulus, the uneven settlement of the top surface of the new widening roadbed shows a downward trend. The characteristics of subgrade soil should be strictly guaranteed by field test during construction. After discussion and study, it is suggested that the slope deviation I 鈮，

本文編號：1416431